It's good to have more than a single person who can edit the website and now you can add and manage your own administrators. When you login you can see at a glance how many administrators you have and when they last logged in.
You can also manage members, which is a useful new feature. Members are not full administrators as they cannot edit the website content. Throughout the site you can configure individual pages to be 'public' or 'members only' - members have login credential like administrators, and when they are logged in they can see members-only pages, which are not visible to normal visitors to your site.